Brass plating bath and brightener composition therefor

ABSTRACT

An additive for a brass electroplating bath which comprises (1) an amine such as diethylene diamine; (2) cyanoethyl glycine or cyanoethyl sucrose; (3) sodium or potassium hydroxide; (4) a compound such as lauroyl sarcosine acid; (5) an ethylene oxide condensate; (6) sodium or potassium nitrate and (7) phenol. Typical bath compositions using said additive to deposit brass are disclosed.

United States Patent [72] Inventor Daniel Richard France 1637 West Third St., Brooklyn, NY. 1 1223 [21 Appl. No. 880,887 [22] Filed Nov. 28, 1969 [45] Patented Sept. 21, 1971 [54] BRASS PLATlNG BATH AND BRIGHTENER COMPOSITION THEREFOR 4 Claims, No Drawings [52] U.S. Cl 204/44, 204/DIG. 2 [5]] Int. Cl C23b 5/36, C23b 5/46 [50] Field of Search 204/44,

DIG. 2, 123; l06/l; ll7/l30E [56] References Cited UNITED STATES PATENTS 2,817,627 12/1957 Ostrow et al.. 204/44 2,838,448 6/l958 France 204/44 2,989,448 6/ l 96] France 204/44 FOREIGN PATENTS 949,60] 2/1964 Great Britain 204/44 949,602 2/1964 Great Britain 204/44 Primary Examiner-G. L. Kaplan Attorney-Francis E. Rinehart ABSTRACT: An additive for a brass electroplating bath which comprises (i) an amine such as cyanoethyl glycine or cyanoethyl potassium hydroxide; (4) a compo cosine acid; (5) an ethylene oxide c potassium nitrate and (7) using said additive to depo diethylene diamine; (2) sucrose; (3) sodium or und such as lauroyl sarondensale; (6) sodium or phenol. Typical bath compositions sit hrassare disclosed.

BRASS PLATING BATH AND BRIGHTENER COMPOSITION THEREFOR This invention relates generally to electroplating and more particularly, to a brass plating composition, bath and brightener.

One of the objects of this invention is to provide a novel electroplating composition, bath and brightener which will cause the metal being deposited to be deposited at high speed and become fine grained, smooth, bright and ductile, while at the same time maintaining the yellow brass color known in the trade as Hardware Brass.

In the prior art of making Hardware Brass" colored electrodepositions, a plating solution is used which deposits an alloy of brass containing from 70 to 80 parts copper to 30 to 20 parts zinc. This conventional solution is operated from 80 to 100 degrees Fahrenheit, contains no free alkali and no Rochelle salts, and deposits brass at relatively slow speeds. Further limitations are the low solubility of the solution and corrosion of the anodes in the plating tank. The solution causes heavy sludge to form on the anodes which requires periodic cleaning of the anodes and removal of the sludge from the solution. Also the low solubility rate of the anodes requires frequent additions of copper and zinc salts to be added to the solution to maintain the metal being deposited from the bath. Color control becomes critical and difficult to maintain because of the constant additions and changes which occur. Moreover, additions of NH OH are required daily as an aid in controlling the alloy resulting in obnoxious odors which are a hazard and hindrance to the operator.

A number of so-called high-speed solutions have been tried to eliminate some of the objections to conventional baths but they do not produce the Hardware Brass" color which is needed and required in the hardware and lamp industries. The color of these high-speed brasses tends to become pale or pinkish in color instead of the deep yellow green color which the conventional slow speed brass plating baths produce.

A particular object of this invention is to produce a highspeed plating composition, bath and brightener which will create the Hardware Brass" color that is so greatly desired.

Other objects of the invention will in part be obvious and in part hereinafter pointed out.

The materials listed in the following Tables I to VII have been found to be effective for making up a brightener in accordance with this invention:

TABLE 1 Diethylene diamine, Diethylene triamine, Triethylene tetramine, or Diethylene pentamine TABLE 11 TABLE I1 Cyanoethyl glycine or cyanoethyl sucrose TABLE III Sodium hydroxide or potassium hydroxide TABLE IV Lauroyl sarcosine acid, Cocoyl sarcosine acid, Oleoyl sarcosine acid, Sodium salt of cocoyl sarcosine, or Sodium salt of lauroyl sarcosine TABLE V Ethylene Ethylene oxide condensate. such as; Merpol or DDN manufactured by E. l. duPont deNernours.

TABLE VI Sodiumnitrate. or potassium nitrate TABLE VII Phenol 98% Liquid.

More specifically, one gallon ofa brightener formulation in accordance with this invention may be made up as follows:

I. 36 ccs ofany one contained in Table 01 2. 2 cc's of any one contained in Table 011 3. 250 Grams of any one contained in Table 0111 4. 250 ccs of any one contained in Table 01V 5. 250 ccs of any one contained in Table 0V 6. 250 Grams of any one contained in Table 0V1 7. ccs ofany one contained in Table 0VlI The materials are mixed in one-half gallon of hot water in the order in which they are above listed. After all chemicals are completely dissolved additional hot water is added to make one gallon of liquid solution. For general purposes a brightener made as set forth above can be used in most, if not all, brass plating solutions and will produce good results.

For optimum results, however, the following are specific formulations for brass plating solutions in accordance with this invention:

MAKE-UP FORMULA Oz. per gal. Sodium cyanide 16.0-19.2 Caustic soda........ Copper cyanide... Zinc cyanide Rochelle salts 0 4: Brightener as in Example 1 l.0|.5 Sodium carbonate 5.0-6.0

MAINTENANCE FORMULA ()2. per gal.

Free sodium cyanide 5.5-6.6 Caustic soda........ .13.0 Copper cyanide... 10.0-12.0 Zinc cyanide .5.6 Rochelle salts 2.0-4.0 1.0*l.5

Brightener The solution is operated from to F. Hull cell tests made on such solutions and run at 2 volts and 2 amperes show full bright deposits from 1 to 84 amperes per square foot. Slow agitation was used during the tests. As thickness increased, so did brightness. Color was matched to 80/20 solid brass polished panels. No distinction could be made between the two.

In the event a brass plating solution in accordance with this invention but containing extremely low sodium hydroxide is desired, the following formula will produce desired results of brightness, color and speed.

BRASS MAKE-UP FORMULA Oz. per gal. Sodium cyanide 13.0

pH: 11.0 to 12.5.

In order to estimate the optimum zinc cyanide content in the above at various temperatures, the following Table will show the necessary increase in the zinc content as the temperature of the plating solution is increased:

Temperature 80-l20 F. Multiply the Copper Cyanide content by the factor .036 Temperature l20-l35 F. Multiply the Copper Cyanide content by the factor .04 Temperature 135l50 F. Multiply the Copper Cyanide content by the factor .07 it will thus be seen that there is provided a composition,

bath, brightener and process by means of which the several Per gallon aqueous solution Diethylene diamine, Diethylene Diethylene diamine, diethylene triamine, triethylene tetramine, or diethylene pentamine, cc... C yanoethyl glycine or cyanoethyl sucrose, cc..... Sodium hydroxide or potassium hydroxide, grams. Lauroyl Lauroyl sarcosine acid, cocoyl sarcosine acid, oleoyi sarcosine acid,

sodium salt of cocoyl sarcosine, or sodium salt oflauroyl sarcosine, cc...

250 Ethylene oxide condensate, cc 250 Per gallon aqueous solution Sodium nitrate or potassium nitrate. grams 250 Phenol-98% liquid, cc

2. A high-speed aqueous brass plating composition for producing Hardware Brass color depositions comprising substantially:

Ounces per gallon Sodium cyanide [6 Copper cyanide. l0 Caustic soda... 3 Zinc cyanide. .5 Rochelle salts. 4 Brightener as in claim I L25 3. A high-speed aqueous brass plating composition for producing Hardware Brass" color depositions comprising substantially:

Ounces per gallon Sodium cyanide Caustic soda Copper cyanide Zinc cyanide Rochelle salts Sodium bicarbonate Brightener as in claim 1....

biota-econ 4. in an aqueous brass electroplating bath the improvement wherein, a brightener as set forth in claim 1, is present in an amount sufficient to provide a fine grained, smooth, bright and ductile brass electrodeposit. 

2. A high-speed aqueous brass plating composition for producing ''''Hardware Brass'''' color depositions comprising substantially:
 3. A high-speed aqueous brass plating composition for producing ''''Hardware Brass'''' color depositions comprising substantially:
 4. In an aqueous brass electroplating bath the improvement wherein, a brightener as set forth in claim 1, is present in an amount sufficient to provide a fine grained, smooth, bright and ductile brass electrodeposit. 